Impact hammer with attached wear member



Dec. 19, 1950. c. SENNHOLTZ 2,534,301

IMPACT HAMMER WITH ATTACHED WEAR MEMBER Filed July 29, 1948 2 Sheets-Sheet 1 Inventor Charlesfisgnnholtg Dec. 19, 1950 v c. E. SENNHOLTZ IMPACT HAMMER WITH ATTACHED WEAR MEMBER 2 Sheets-Sheet 2 Filed July 29, 1948 bufientor Charlesfi nnholt b W) Patented Dec. 19, 1950 WITH AT'QA E EFQ West nsMBER Charles s ennholtz Chicago, Ill. e n eetien is! 9 1948; t el 12-4 waves a e- 9 s same ij id 'th iii tt s o ee e s t i a were s ree???- wa Q n o prpyid ha me th irseii at w? @i ee se d 1) a l e eetriresal and se qt 2 1 e t9 cease re r s eds and i n w 9 the a com anr n si la i ies in which:

Figure e rear el va on of hamm and replaceable tip vconstrncted in accordance vyyith the pres nt i n iq H was is asid el ratiq in martia 755C519? t kes alon ithe li i lof E- 1.

3 is a 1301 NEW of the replaceable tip with onewall:thereofincpantial section.

@igi 4 is a perspective view of the hammer arm. :Fig. 5shows .the improved hammertip in pers pecitye with the fade exposed as under operat- 'ing conditions.

is rear perspective view of "the hamreen;gnawed-m rage; Fi odiiication in which the anon Ltegifal the fpflaceahle :il? the invention is susceptibl of zvgrious I, V. a g

2 ha e s own in the d aw n s nd will herein de ble n a e ii e rre QmPQdm E ii :9 be. umie s o tha I e here y fi tied a lim t t e in eneq o. h sn i e. are i closed b t intend' ove l meq e I an alternative const ions nd assign; 3 w in s t and c p b1 the inve ts, expressed in the appended claims' "R fe in mo art ula to he d wi gs a mp t hammer Q embq n thenreseet in= vention is adapted for i sefin various t es and kindsof crushers, pulizeri zers or mills. Ifheh nier' construction may be readily" un without reference to the details ofthepnl r1 asa whole. It will sufiicet'o say; therefore, th a plurality of 'such hammers are pivot v at periphery of a rotating disk. and are maint i in a radially extending direc'tionduefto t tibn of centrifugal force. The harnrn swung successively" into contact with rock, coal or similar frangible material broken up into a loose mass by t e "irnpa As disclosed in Figs. an "z theh comprises a hammer arm or shank ll a mer tip I2 secnred to its lower port on. hammer arm'is pivoted pendulum-like at 1 upper end on a shaft I4 which'is receiyed'in a bore 15; Rectangular in shape,'the arm has a leading edge I6 and side walls l8,' [9 extending rearwardly .therefrorn It will be noted that cooperating tip I2 is generally box-like having a relatively massive impact face 22 and side walls 2 25. Interiorally the tip is hollowed or nelled-out to provide a recess 26 into which the lower portion of the hammer arm I l is slidahly inserted. When in position on the arm, the ,tip substantially encloses the entire lower portion of the arm. Preferably the face of the tip ispro- .yi ded with anupward extension 2 8 to protect the leading edge of the arm and to serve as a Inm nt; ing for a threaded fastener.

In accordance with one of the aspectsof the invention, the arm H and replaceable tip 1.2 are Joined by a. tongue groove connection itch is sjo constrncted'that centrifugal force actingon the relatively massiige tip 12 tendstowedge the tip onto the arm increasinglydnring normal use ofthehammer. In the pre'sent construction this is accomplished by providing internal tongues "39; v 3l on the interior yvalls of the tip and; y" lieiiingithe lower portion of the'arm :topro de downwardly angled engaging shoulders "or fle ges 3;, 35. 'As how n E 252 invariants an angle A Withrespect to the radial dime" 91' the arm so that engagement is accorn red by a small amount of radially outward movement. Thus, with the tongues 30, 3| engaged on the shoulders 34, 35, there is tendency for the tongues to slide downhill on the shoulders as the result of centrifugal action. Such movement is, however, limited by the wedging engagement to which more detailed reference will be made and ultimately by bottoming of the leading edge It of the arm on the forward wall of the recess 25. It will be apparent that due to the downward angling of the shoulders 34, 35 and the cooperating tongues 30, 3|, assembly of the tip on the arms requires that the tip be slid rearwardly and downwardly into position when the tip and arm are assembled.

Provision is also made for firmly wedging the parts together as a result of forces resulting from normal use. This is accomplished in part by the specific tapered construction of the tongues 30, 3! and of cooperating grooves 38, 39

lying adjacent the shoulders 34, 35. As will be noted from the drawings, the grooves 38, 39 formed on the lateral faces of the hammer arm are tapered, the width of the grooves being ape preciable at the point of intersection with the leading edge is of the hammer arm while the trailing portions thereof are considerably narrower. It will be clear upon inspection of Fig. 6 that the inserted tongues 3! 36 are likewise tapered both horizontally and vertically so that upon insertion into the grooves 33, 39 bearing will take place evenly on both the side walls and the roots of the grooves. Not only does such construction provide a firm grip between the tip and hammer arm, but it also results in a sturdy column-like construction of the tongues 30, 3! which flare evenly in the direction of the face 22 for absorbing the impact stresses.

In another aspect of the invention it will be noted that the grooves 38, 39 define a boss or enlargement generally indicated at 45 having side walls l8a, 19a and a lower surface 41 adapted for insertion into the recess 26. Further, the boss 40 is tapered both horizontally and vertically so that, from a structural standpoint, it may be compared to a truncated pyramid, with the leading portion of the boss being of reduced cross section. In order to utilize all of the gripping area thus made available, the walls of the recess 26 in the tip l2 are likewise tapered and to the same degree. Consequently, insertion of the boss 40 into the recess is accompanied by wedging at the surfaces [8a, l9a., 4| as well as on the shoulders 34, 35 previously referred to. It will be apparent, therefore, since all of the mating surfaces are tapered, that there are no surfaces which need be machined to a fine tolerance in order to insure smooth sliding engagement. As a matter of fact, the tip !2 may be a simple casting and may be constructed as illustrated without any machining whatsoever. Since it is unnecessary that the tip I2 be precisely fitted to the arm II to avoid looseness or play, it will be apparent that considerable dimensional variation is permissible, and the tips may be turned out very cheaply. The latter point is of particular interest when it is remember that the tip must be replaced at intervals due to the abrasion by the pulverized material in which it operates. Where the tips are formed of cast steel it will be seen that the tapered surfaces provide proper draft for easy removal of the pattern from the mold.

One of the advantages resulting from the tapering of the boss 40 and the recess 26 is particu f sistance to abrasion.

larly well illustrated in Figs. 2 and 3 where it will be seen that the lower and side walls of the tip I2 are flared into a thick supporting cross section in the region 42 without undue enlargement of the tip. This not only provides a strong columnar support for the peripheral portions of the impact face 22 which must take the brunt of the wear, but also provides considerable metal which may be worn away due to abrasion before replacement becomes necessary. As a result, it has been found that tips of the present construction may be kept in service for a length of time which compares favorably to relatively expensive hammer tips of the reversible type having renewable faces. The saving using the present type of tip is even greater than might be expected since taking the machine out of service and disassembling it at frequent intervals for renewing the tips becomes unnecessary.

To increase the gripping action and to provide a mounting for a fastening bolt the upward extension 28 of the face 22 carries a transverse tongue 45 on the rear portion thereof, This tongue includes tapered sides 48, 49 which are received in a registering notch which is formed in the leading edge E6 of the hammer arm. While it will be apparent to one skilled in the art that the tongue 45 serves to retain the tip against radial displacement, it is to be particularly noted that the tongue is well adapted for preventing relative twisting to the tip l2 on the arm caused by severe impact at the lower portion of the impact face 22. In understanding this function of the tongue 45 it is helpful to consider the hammer tip as analogous to ones cupped hand and the tongu 45 as analogous to gripping finger tips resisting downward rotation of the hand.

In order to fasten the tip I2 on the arm II and to positively lock it in place thereon, a bolt 46 is provided which is received in a bore 53 drilled into the leading edge of the hammer arm. At its trailing end the bolt 46 includes a head 54 which is recessed in a countersunk hole 55. Preferably a fillister head cap screw is used.

At the forward end of the bolt 46 means are provided for threaded engagement. Preferably this is accomplished by recessing a nut 5| in a T slot 52 which lies behind the face 22 in a protected position. The latter has the advantage that the nut may be inserted immediately prior to installing the hammer tip. Consequently, the threads are not aifected by the heat treating processes to which the tip may be subjected during manufacture to increase its strength and re- If desired, however, the bolt may engage the tongue 45 directly as dis closed at 45a in Fig. '7. It will be apparent, too, that forming the bolt integrally with the tip and providing it with a fastening nut at its trailing end is included within the scope of the present invention. In those cases where an integral bolt (or stud) is employed, it is important to observe that the bolt and its cooperating bore 53 are angled downwardly at an angle which is the same as the angle A of sliding movement of the tongues 30, Si in the cooperating grooves 38, 39. Regardless of which specific fastening means is employed, it will be apparent that the direction of pull on the tip I2 is in the same direction as the direction of relative sliding movement between the two. Because of the engagement of the tapered faces previously discussed, it has been found that th bolt is not subjectto any stress Other than that incident to its initial axial tightening.

In spite of the fact that the tip is wedged into firm engagement on the hammer by the forces incident to its use, it is significant that replacement is readily accomplished. It is merely necessary to remove the bolt 46 and to ta the worn tip I2 forwardly with a machinists hammer. This immediately relases the wedging forces and enables the tip to be readily withdrawn. Since both the engaging surfaces and the fastening bolt are completely shielded, injury to the latter is completely avoided and a renewal tip may be quickly fastened in place.

I claim as my invention:

1. An impact hammer for rotary pulverizers comprising, adapted to be supported for bodily swing at one end and having lateral shoulders at the other end extending generally perpendicular to the longitudinal dimension of said arm, a hammer tip comprising a hollowed-out body portion and an impact face, said hollowed-out body portion having opposed inwardly directed tongues for engagement by the shoulders on said arm, said face portion having at its upper edge a transverse rearwardly facing tongue, said tongue having formed. in the upper surface thereof a T slot for the reception of a nut, and a bolt extending through said arm for tightening engagement with said nut.

2. An impact hammer for rotary pulverizers comprising, in combination, a hammer arm adapted to be supported at one end for bodily swing, said arm being necked down at its opposite end to define a boss arranged in general alinement with the direction of swinging movement of said outer end, said boss having outer surfaces which flare both horizontally and vertically in a rearward direction, and a hammer tip having an impact face, said tip being channeledout rearwardly of said face to provide internal surfaces registering with the outer surfaces of said boss, the flared nature of said surfaces enabling snug engagement of said tip in spite of surface inaccuracy.

3. An impact hammer for rotary pulverizers comprising, in combination, a hammer arm adapted to be supported at one end for bodily swing, said arm being necked down at its upposite end to define a boss arranged in general alinement with the direction of swinging movement of said outer end, said boss having a truncated pyramidal shape with the leading portion thereof being of reduced cross section, and a metal hammer tip having an impact face and channeled-out rearwardly of said face to form a rearwardly flaring recess for registering with said boss, said tip having a wedge-shaped cross section of metal bounding said recess and serving not only to reinforce said face under impact but to permit wearing away of the periphery of said face'as a result of abrasion.

4. An impact hammer for rotary pulverizers comprising, in combination, a hammer arm adapted to be supported at one end, said arm in combination, a hammer arm having a leading edge and generally parallel side surfaces adjacent thereto, said side surfaces each being relieved by a groove formed therein which intersects said leading edge and which extends rearwardly therefrom, a hammer tip of box-like construction having a massive impact face portion and side walls extending rearwardly therefrom, said side walls having formed therein opposed tongues adapted for registered engagement with the grooves in said hammer arm, a threaded fastener extending through said hammer arm toward the leading edge thereof, and a nut for. engagement with the forward end of said threaded fastener, said impact face portion being channeled out to provide a rearwardly facing pocket which is T-shaped in transverse section for the reception of said nut and dimensioned to prevent turning of the latter.

5. An impact hammer for rotary pulverizers comprising, in combination, a hammer arm adapted to be supported at one end, said arm having a leading edge and bottom and side surfaces adjacent thereto, each of said bottom and side surfaces being flared outwardly in a direction rearwardly of the leading edge, said side surfaces each being relieved by a groove formed therein which intersects said leading edge and which extends at an angle rearwardly and downwardly therefrom, a hammer tip of box-like construction having a massive impact face and having bottom and side walls extending rearwardly therefrom to mate with corresponding bottom and side surfaces of said arm, said side walls having formed therein opposed tongues adapted for registered engagement with the grooves in said hammer arm, an upward extension on the face portion of said tip having a transverse rearwardly extending tongue and a rearwardly opening pocket, said arm having formed in its leading edge a notch for the receipt of said rearwardly facing tongue, a bolt extending through said hammer arm toward the leading edge thereof, and means disposed in said pocket for threaded engagement with said bolt so that said tongues may be drawn inwardly and downwardly into said grooves.

CHARLES E. SENNI-IOLTZ.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,456,987 Lucas May 29, 1923 1,643,874 Cawood Sept. 27, 1927 1,717,759 Briggs June 18, 1929 1,996,485 Parker Apr. 2, 1935 2,148,547 Fiese Feb. 28, 1939 2,318,219 Harris May 4, 1943 2,392,958 Tice Jan. 15, 1946 2,429,157 Fowler Oct. 14, 1947 2,467,865 Smith Apr. 19, 1949 

